Transmit power determining method, processing chip, and communications device

ABSTRACT

A communication method is provided, including: determining, by a first device, a relative power ratio between a phase tracking reference signal (PTRS) and a data channel; determining, by the first device, a transmit power of the PTRS based on the relative power ratio of the PTRS to the data channel; and sending, by the first device, the PTRS to a second device by using the transmit power of the PTRS.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/855,686, filed on Apr. 22, 2020, which is a continuation of U.S.patent application Ser. No. 16/204,879, filed on Nov. 29, 2018, now U.S.Pat. No. 10,652,829. which claims a continuation of InternationalApplication No. PCT/CN2018/091226, filed on Jun. 14, 2018, which claimspriority to Chinese Patent Application No. 201710459810.7, filed on Jun.16, 2017 and Chinese Patent Application No. 201710698502.X, filed onAug. 15, 2017. All of the afore-mentioned patent applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of the present disclosure relate to the field ofcommunications technologies, and in particular, to a transmit powerdetermining method, a processing chip, and a communications device.

BACKGROUND

In comparison with Long Term Evolution (LTE), a higher carrier frequencyis used in a 5G communications system. A current standard stipulatesthat a high frequency is usually above 6 GHz, and a currently mostresearched band is 28 GHz, 38 GHz, 72 GHz, or the like, to implementwireless communication with higher bandwidth and a higher transmissionrate. However, in comparison with conventional low-frequencycommunication, a high frequency system has more serious intermediateradio frequency distortion, especially impact of phase noise. Inaddition, impact of a Doppler shift and a carrier frequency offset (CFO)increases with a frequency.

In an example of multiple-input multiple-output orthogonal frequencydivision multiplexing (MIMO-OFDM), both phase noise and a carrierfrequency offset of a receive end and those of a transmit end areconsidered, and a reception expression of an n^(th) receive antenna on ak^(th) subcarrier after the receive end performs fast Fourier transform(FFT) is:

${Y_{n}^{k} = {{\sum\limits_{m = 1}^{M}\;{H_{n\; m}^{k}\underset{\underset{CPE}{︸}}{P_{n}^{r,G}P_{m}^{t,0}}S_{m}^{k}}} + \underset{\underset{ICI}{︸}}{\sum\limits_{m = 1}^{M}{\sum\limits_{t = 0}^{K - 1}{P_{n}^{r,{{({k - 1})}K}}H_{n\; m}^{i}{\sum\limits_{{i = 0},{{{{i\; \neq 1}\&}i} \neq k}}^{K - 1}{P^{t,{({i - 1})}}S_{m}^{l}}}}}} + Z_{n}^{k}}};$     where$\mspace{79mu}{{P_{n}^{r,k} = {\frac{1}{K}{\sum\limits_{t = 0}^{K - 1}{e^{j\;{\theta_{n}^{r}{(t)}}}e^{j\; 2\;\pi\;{{tk}/K}}}}}},\mspace{79mu}{P_{m}^{t,k} = {\frac{1}{K}{\sum\limits_{t = 0}^{K - 1}{e^{j\;{\theta_{m}^{t}{(t)}}}e^{j\; 2\;\pi\;{{tk}/K}}}}}},\mspace{79mu}{{namely}\text{:}}}$$\mspace{79mu}{{P_{n}^{r,0} = {\frac{1}{K}{\sum\limits_{t = 0}^{K - 1}e^{j\;{\theta_{n}^{r}{(t)}}}}}},\mspace{79mu}{P_{m}^{t,0} = {\frac{1}{K}{\sum\limits_{t = 0}^{K - 1}{e^{j\;{\theta_{m}^{t}{(t)}}}.}}}}}$

H_(nm) ^(k) represents a channel from an m^(th) transmit antenna to then^(th) receive antenna on the k^(th) subcarrier, S_(m) ^(k) representsdata sent by using the m^(th) transmit antenna on the k^(th) subcarrier,Z_(n) ^(k) represents noise of the n^(th) receive antenna on the k^(th)subcarrier, P_(n) ^(r,k) represents a phase deviation caused by thephase noise and the CFO of the receive end for the n^(th) receiveantenna on the k^(th) subcarrier, and P_(m) ^(t,k) represents a phasedeviation caused by the phase noise and the CFO of the transmit end foran m^(th) transmit antenna on the k^(th) subcarrier. It can be learnedfrom the expression that impact of phase noise on OFDM performance ismainly reflected in two aspects: a common phase error (CPE) andinter-carrier interference (ICI), and impact of CFO on OFDM performanceis mainly reflected in ICI. In an actual system, the impact of the ICIon the performance is less than the impact of the CPE on theperformance. Therefore, the CPE is preferentially compensated for in aphase noise compensation scheme.

FIG. 1A shows a constellation point at which a 64QAM modulation signalis not affected by phase noise. FIG. 1B shows a constellation point atwhich a 64 quadrature amplitude modulation (QAM) signal on a 2G band isaffected by phase noise. FIG. 1C shows a constellation point at which a64 QAM modulation signal on a 28G band is affected by phase noise. Asshown in FIG. 1A to FIG. 1C, phase noise is used as an example, and aphase noise level deteriorates with a band at a level of20×log^((f1/f2)). A 2G band and a 28G band are used as an example, and aphase noise level of the 28G band is higher than that of the 2G band by23 dB. A higher phase noise level causes greater impact of a commonphase error, and the CPE causes a bigger phase error.

A CPE imposes same impact on different subcarriers of a same OFDMsymbol, and phase errors on the different subcarriers are differentbecause of white Gaussian noise. Therefore, in frequency domain, aspecific quantity of phase compensation reference signals (PCRS) needsto be used to estimate the CPE and calculate an average, to reduceimpact of the white Gaussian noise as much as possible. PCRS may also bereferred to as phase tracking reference signals (PTRS). PCRS is notuniformly named currently in the industry, but is uniformly referred toas the PTRS subsequently for convenience in the present disclosure.

Currently, how to determine transmit power of a PTRS is a technicalproblem that needs to be urgently resolved.

SUMMARY

Embodiments of this application provide a transmit power determiningmethod, so as to flexibly adapt to different quantities of demodulationreference signal (DMRS) ports, different quantities of PTRS ports, ordifferent port multiplexing manner configurations, thereby ensuringefficient energy use, and improving PTRS measurement accuracy.

According to a first aspect, an embodiment of this application providesa transmit power determining method, including: determining, by a firstdevice, a relative power ratio of a phase tracking reference signal PTRSto a data channel or a relative power ratio of a PTRS to a demodulationreference signal DMRS, where the relative power ratio of the PTRS to thedata channel is determined by using a first function and a firstvariable, the relative power ratio of the PTRS to the DMRS is determinedby using a second function, the first variable, and a second variable,the first variable includes a quantity of transport layers or a quantityof DMRS ports, and the second variable includes a frequency domaindensity of the DMRS; determining, by the first device, transmit power ofthe PTRS based on the relative power ratio of the PTRS to the datachannel and transmit power of the data channel or based on the relativepower ratio of the PTRS to the DMRS and transmit power of the DMRS; andsending, by the first device, the PTRS to a second device by using thetransmit power of the PTRS.

According to the first aspect, in a possible implementation, the firstdevice includes a terminal device, the second device includes a basestation device, and the data channel includes a physical uplink sharedchannel (PUSCH).

According to the first aspect, in a possible implementation, the firstdevice includes a base station device, the second device includes aterminal device, and the data channel includes a physical downlinkshared channel (PDSCH).

According to the first aspect and all the possible implementations ofthe first aspect, in a possible implementation, that the relative powerratio of the PTRS to the data channel is determined by using a firstfunction and a first variable includes:relative power ratio of the PTRS to the data channel=10 log₁₀(X), where

X includes the first variable.

According to the first aspect and all the possible implementations ofthe first aspect, in a possible implementation, that the relative powerratio of the PTRS to the DMRS is determined by using a second function,the first variable, and a second variable includes:relative power ratio of the PTRS to the DMRS=10 log₁₀(XY), where

X includes the first variable, and Y includes the second variable.

According to a second aspect, an embodiment of this application providesa transmit power determining method, including: searching, by a firstdevice, a table to determine a relative power ratio of a phase trackingreference signal (PTRS) to a data channel or a relative power ratio of aPTRS to a demodulation reference signal (DMRS); determining, by thefirst device, transmit power of the PTRS based on the relative powerratio of the PTRS to the data channel and transmit power of the datachannel or based on the relative power ratio of the PTRS to the DMRS andtransmit power of the DMRS; and sending, by the first device, the PTRSto a second device by using the transmit power of the PTRS.

According to the second aspect, in a possible implementation, the firstdevice includes a terminal device, the second device includes a basestation device, and the data channel includes a physical uplink sharedchannel (PUSCH).

According to the second aspect, in a possible implementation, the firstdevice includes a base station device, the second device includes aterminal device, and the data channel includes a physical downlinkshared channel (PDSCH).

According to the second aspect and all the possible implementations ofthe second aspect, in a possible implementation, the searching, by afirst device, a table to determine a relative power ratio of a PTRS to adata channel includes:

searching, by the first device, the following table to determine therelative power ratio of the PTRS to the data channel:

Quantity of Relative power ratio transport (dB) of the PTRS to thelayers PUSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

or

Relative power ratio Quantity of (dB) of the PTRS to the DMRS portsPUSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

According to the second aspect and all the possible implementations ofthe second aspect, in a possible implementation, the searching, by afirst device, a table to determine a relative power ratio of a PTRS to adata channel includes:

searching, by the first device, the following table to determine therelative power ratio of the PTRS to the data channel:

Quantity of transport Relative power ratio (dB) of the layers PTRS tothe PDSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

or

Quantity of DMRS Relative power ratio (dB) ports of the PTRS to thePDSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

According to the second aspect and all the possible implementations ofthe second aspect, in a possible implementation, the searching, by afirst device, a table to determine a relative power ratio of a PTRS to aDMRS includes:

searching, by the first device, the following table to determine therelative power ratio of the PTRC to the DMRS:

Quantity of Frequency domain Relative power ratio (dB) of transportlayers density of the DMRS the PTRS to the DMRS 1 1/4 (−)6 2 1/4 (−)3 31/4 (−)1.23 4 1/4 0 5 1/4 0 6 1/4 0 7 1/4 0 8 1/4 3

or

Frequency domain Relative power ratio Quantity of density of the (dB) ofthe PTRS DMRS ports DMRS to the DMRS 1 1/4 (−)6 2 1/4 (−)3 3 1/4 (−)1.234 1/4 0 5 1/4 0 6 1/4 0 7 1/4 0 8 1/4 3

According to a third aspect, an embodiment of this application providesa processing chip, configured to: determine a relative power ratio of aphase tracking reference signal (PTRS) to a data channel or a relativepower ratio of a PTRS to a demodulation reference signal (DMRS), wherethe relative power ratio of the PTRS to the data channel is determinedby using a first function and a first variable, the relative power ratioof the PTRS to the DMRS is determined by using a second function, thefirst variable, and a second variable, the first variable includes aquantity of transport layers or a quantity of DMRS ports, and the secondvariable includes a frequency domain density of the DMRS; and determinetransmit power of the PTRS based on the relative power ratio of the PTRSto the data channel and transmit power of the data channel or based onthe relative power ratio of the PTRS to the DMRS and transmit power ofthe DMRS.

According to the third aspect, in a possible implementation, the datachannel includes a physical uplink shared channel (PUSCH) or a physicaldownlink shared channel (PDSCH).

According to the third aspect and all the possible implementations ofthe third aspect, in a possible implementation, that the relative powerratio of the PTRS to the data channel is determined by using a firstfunction and a first variable includes:relative power ratio of the PTRS to the data channel=10 log₁₀(X), where

X includes the first variable.

According to the third aspect and all the possible implementations ofthe third aspect, in a possible implementation, that the relative powerratio of the PTRS to the DMRS is determined by using a second function,the first variable, and a second variable includes:relative power ratio of the PTRS to the DMRS=10 log₁₀(XY), where

X includes the first variable, and Y includes the second variable.

According to a fourth aspect, an embodiment of this application providesa processing chip, configured to: search a table to determine a relativepower ratio of a phase tracking reference signal (PTRS) to a datachannel or a relative power ratio of a PTRS to a demodulation referencesignal (DMRS); and determine transmit power of the PTRS based on therelative power ratio of the PTRS to the data channel and transmit powerof the data channel or based on the relative power ratio of the PTRS tothe DMRS and transmit power of the DMRS.

According to the fourth aspect, in a possible implementation, the datachannel includes a physical uplink shared channel (PUSCH).

According to the fourth aspect and all the possible implementations ofthe fourth aspect, in a possible implementation, the data channelincludes a physical downlink shared channel (PDSCH).

According to the fourth aspect and all the possible implementations ofthe fourth aspect, in a possible implementation, the searching a tableto determine a relative power ratio of a PTRS to a data channelincludes:

searching the following table to determine the relative power ratio ofthe PTRS to the data channel:

Quantity of Relative power ratio (dB) transport layers of the PTRS tothe PUSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

or

Quantity of Relative power ratio (dB) DMRS ports of the PTRS to thePUSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

According to the fourth aspect and all the possible implementations ofthe fourth aspect, in a possible implementation, the searching a tableto determine a relative power ratio of a PTRS to a data channelincludes:

searching the following table to determine the relative power ratio ofthe PTRS to the data channel:

Quantity of Relative power ratio (dB) transport layers of the PTRS tothe PDSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

or

Quantity of Relative power ratio (dB) DMRS ports of the PTRS to thePDSCH 1 0 2 3 3 4.77 4 6 5 7 6 7.78 7 8.45 8 9

According to the fourth aspect and all the possible implementations ofthe fourth aspect, in a possible implementation, the searching a tableto determine a relative power ratio of a PTRS to a DMRS includes:

searching the following table to determine the relative power ratio ofthe PTRS to the DMRS:

Quantity of Frequency domain Relative power ratio (dB) transport layersdensity of the DMRS of the PTRS to the DMRS 1 1/4 (−)6 2 1/4 (−)3 3 1/4(−)1.23 4 1/4 0 5 1/4 0 6 1/4 0 7 1/4 0 8 1/4 3

or

Frequency domain Relative power ratio Quantity of density of the (dB) ofthe PTRS DMRS ports DMRS to the DMRS 1 1/4 (−)6 2 1/4 (−)3 3 1/4 (−)1.234 1/4 0 5 1/4 0 6 1/4 0 7 1/4 0 8 1/4 3

According to a fifth aspect, this application provides a communicationsdevice, including a processor and a transmitter. The communicationsdevice is configured to perform the method provided in the first aspectand all the possible implementations of the first aspect.

According to a sixth aspect, this application provides a communicationsdevice, including a processor and a transmitter. The communicationsdevice is configured to perform the method provided in the second aspectand all the possible implementations of the second aspect.

According to a seventh aspect, this application provides a transmitpower determining method, including: mapping, by a first device, data toa plurality of transport layers, where the plurality of transport layersinclude a first transport layer, the first transport layer iscorresponding to a first RE set and a second RE set, the first RE setand the second RE set each include a plurality of REs, each RE in thefirst RE set is mapped to a phase tracking reference signal (PTRS), andeach RE in the second RE set cannot be used for data mapping;increasing, by the first device by using power of all REs in the secondRE set, transmit power of PTRSs mapped to all REs in the first RE set;and sending, by the first device, the PTRS by using increased transmitpower.

According to an eighth aspect, an embodiment of this applicationprovides a communications device, including: a processor, configured to:map data to a plurality of transport layers, where the plurality oftransport layers include a first transport layer, the first transportlayer is corresponding to a first RE set and a second RE set, the firstRE set and the second RE set each include a plurality of REs, each RE inthe first RE set is mapped to a phase tracking reference signal PTRS,and each RE in the second RE set cannot be used for data mapping; andincrease, by using power of all REs in the second RE set, transmit powerof PTRSs mapped to all REs in the first RE set; and a transmitter,configured to send the PTRS by using increased transmit power.

In the embodiments of this application, a transmit end device firstobtains the relative power ratio of the PTRS to the data channel or tothe DMRS by searching a table or through calculation, determines thetransmit power of the PTRS based on the transmit power of the datachannel or the transmit power of the DMRS, and sends the PTRS by usingthe transmit power, so that different quantities of DMRS ports,different quantities of PTRS ports, and different port multiplexingmanner configurations can be flexibly adapted, thereby ensuringefficient energy use.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure clearly, the following briefly describes the accompanyingdrawings for describing the embodiments or the conventional art.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present disclosure, and a person ofordinary skill in the art may derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1A shows a constellation point at which a 64QAM modulation signalis not affected by phase noise;

FIG. 1B shows a constellation point at which a 64QAM modulation signalon a 2G band is affected by phase noise;

FIG. 1C shows a constellation point at which a 64QAM modulation signalon a 28G band is affected by phase noise;

FIG. 2 is a schematic structural diagram of an application scenarioaccording to an embodiment of this application;

FIG. 3 is a diagram of a resource grid in an LTE system;

FIG. 4A is a schematic diagram of a pilot pattern according to anembodiment of this application (uplink transmission, one transportlayer, one DMRS port, and one PTRS port);

FIG. 4B-1 and FIG. 4B-2 are schematic diagrams of pilot patternsaccording to an embodiment of this application (uplink transmission, twotransport layers, two DMRS ports, and one PTRS port, where the two DMRSports are grouped into one group);

FIG. 4C-1 and FIG. 4C-2 are schematic diagrams of pilot patternsaccording to an embodiment of this application (uplink transmission, twotransport layers, two DMRS ports, and two PTRS ports, where the two DMRSports are grouped into two groups);

FIG. 5 is a schematic flowchart of a transmit power determining methodaccording to an embodiment of this application; and

FIG. 6 is a schematic structural diagram of hardware of a communicationsdevice according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following further describes in detail this application withreference to accompanying drawings.

The embodiments of this application can be applied to various mobilecommunications systems, such as a Global System for MobileCommunications (GSM), a Code Division Multiple Access (CDMA) system, aWideband Code Division Multiple Access (WCDMA) system, a general packetradio service (GPRS), a Long Term Evolution (LTE) system, a Long TermEvolution Advanced (LTE-A) system, a Universal Mobile TelecommunicationsSystem (UMTS), an evolved Long Term Evolution (eLTE) system, a 5G system(for example, a new radio (NR) system), and other mobile communicationssystems.

Some terms in this application are described below to facilitateunderstanding.

(1) A terminal is also referred to as user equipment (UE), and is adevice that provides voice and/or data connectivity for a user, forexample, a handheld device or an in-vehicle device with a wirelessconnection function. For example, a common terminal includes a mobilephone, a tablet computer, a notebook computer, a palmtop computer, amobile Internet device (MID), and a wearable device such as a smartwatch, a smart band, or a pedometer.

(2) A network device may be a base transceiver station (BTS) in a GSMsystem or a CDMA system, a NodeB (NB) in a WCDMA system, an evolvedNodeB (eNB or eNodeB) in an LTE system, or a wireless controller in acloud radio access network (CRAN). Alternatively, the network device maybe a network device in a future 5G network, for example, a gNB, a smallcell, a micro cell, or a transmission reception point (TRP) in an NRsystem, or may be any other wireless access device such as a relaystation, an access point, or a network device in a future evolved publicland mobile network (PLMN). However, the embodiments of this applicationare not limited thereto.

(3) The term “a plurality of” refers to two or more. The term “and/or”describes an association relationship for describing associated objectsand represents that three relationships may exist. For example, A and/orB may represent the following three cases: Only A exists, both A and Bexist, and only B exists. The character “I” generally indicates an “or”relationship between the associated objects. In addition, it should beunderstood that although the terms “first”, “second”, “third”, and thelike may be used in the embodiments of this application to describevarious messages, requests, and terminals, these messages, requests, andterminals are not limited to these terms. These terms are merely used todistinguish between the messages, requests, and terminals.

FIG. 2 is a schematic structural diagram of an application scenario ofthe embodiments of this application. A networking architecture shown inFIG. 2 mainly includes a base station 101 and a terminal 102. The basestation 101 may communicate with the terminal 102 by using amillimeter-wave band with a low frequency (mainly below 6 GHz) or arelatively high frequency (above 6 GHz). For example, themillimeter-wave band may be 28 GHz, 38 GHz, or an enhanced band of adata plane with a relatively small coverage area, for example, a bandabove 70 GHz. The terminal 102 covered by the base station 101 maycommunicate with the base station 101 by using a millimeter-wave bandwith a low frequency or a relatively high frequency. FIG. 2 is merely anexample of a simplified schematic diagram, and a network may furtherinclude another device that is not shown in FIG. 2 .

A communication method and a communications device provided in theembodiments of this application can be applied to a terminal, and theterminal includes a hardware layer, an operating system layer runningabove the hardware layer, and an application layer running above theoperating system layer. The hardware layer includes hardware such as acentral processing unit (CPU), a memory management unit (MMU), and amemory (also referred to as a main memory). An operating system may beany one or more of computer operating systems that implement serviceprocessing by using a process, for example, a Linux operating system, aUNIX operating system, an Android operating system, an iOS operatingsystem, or a Windows operating system. The application layer includesapplications such as a browser, a contact list, word processingsoftware, and instant messaging software.

In addition, aspects or features of this application may be implementedas a method, an apparatus, or a product that uses standard programmingand/or engineering technologies. The term “product” used in thisapplication covers a computer program that can be accessed from anycomputer readable component, carrier or medium. For example, a computerreadable medium may include but is not limited to a magnetic storagecomponent (for example, a hard disk, a floppy disk, or a magnetic tape),an optical disc (for example, a compact disc (CD) or a digital versatiledisc (DVD)), a smart card, and a flash memory component (for example, anerasable programmable read-only memory (EPROM), a card, a stick, or akey drive). In addition, various storage media described in thisspecification may indicate one or more devices and/or other machinereadable media for storing information. The term “machine readablemedia” may include but is not limited to various media that can store,contain, and/or carry an instruction and/or data.

To better understand this application, the following describes thisapplication with reference to the accompanying drawings.

Embodiment 1

FIG. 3 is a diagram of a resource grid in an LTE system. As shown in thediagram, a channel is sent in a form of consecutive radio frames in theLTE system. One radio frame includes 10 subframes, a length of eachsubframe is 1 millisecond (ms), each subframe includes two timeslots(slot), and each slot is 0.5 ms. A quantity of symbols included in eachslot is associated with a length of a cyclic prefix (CP) in a subframe.If the CP is a normal CP, each slot includes seven symbols, and eachsubframe includes 14 symbols. If the CP is an extended CP, each slotincludes six symbols, and each subframe includes 12 symbols. A downlinksymbol is referred to as an orthogonal frequency division multiplexing(OFDM) symbol. In the LTE system, a resource element (RE) is a minimumunit in time-frequency domain, and is uniquely identified by an indexpair (k, l), where k is a subcarrier index, and l is a symbol index.

Compared with an existing wireless communications network, anext-generation wireless communications network that works in a range ofabove 6 GHz suffers more serious intermediate radio frequencydistortion, especially impact of phase noise. A higher phase noise levelcauses greater common phase error (CPE) impact. Therefore, a phasetracking reference signal (PTRS) is introduced for phase noiseestimation.

However, the PTRS occupies some REs, and the occupied RE is originallyused to send a data channel or another reference signal. During uplinktransmission, the data channel includes a physical uplink shared channel(PUSCH), and during downlink transmission, the data channel includes aphysical downlink shared channel (PDSCH). A most common case is that theoccupied RE is originally used to send the data channel. In this case,total power of the PTRS needs to be equal to total power of the datachannel that is originally to be sent in the occupied RE (“power” inthis embodiment of this application is equivalent to “transmit power”).Total available power of a transmit end is preconfigured. Therefore, iftransmit power of the PTRS is greater than transmit power of the datachannel that is originally to be sent in the occupied RE, the totalavailable power is exceeded. If the transmit power of the PTRS is lessthan the transmit power of the data channel that is originally to besent in the occupied RE, a power waste is caused. Certainly, it isfeasible that the transmit power of the PTRS is only slightly less thanthe transmit power of the data channel that is originally to be sent inthe occupied RE (a difference does not exceed a preset threshold).

In an example of uplink transmission, if the transmit power of the PTRSis equal to the transmit power of the data channel that is originally tobe sent in the occupied RE, a formula (1) may be obtained:N _(layers) ×N _(RE/layers) ×P _(PUSCH) =N _(PTRS ports) ×N_(REI PTRS ports) ×P _(PTRS)  (1)

N_(layers) is a quantity of transport layers, N_(REI layers) is aquality of REs at each transport layer that cannot be used because ofthe PTRS (in one resource block (RB) and one OFDM symbol), P_(PUSCH) ispower of a PUSCH at the transport layer (in one RE), N_(PTRS ports) is aquantity of PTRS ports, N_(REI PTRS ports) is a quantity of REs occupiedby each PTRS port (in one RB and one OFDM symbol, where it is assumedthat the quantity of REs is 1 herein), and P_(PTRS) is the power of thePTRS (in one RE).

A formula (2) may be further obtained according to the formula (1):

$\begin{matrix}{\frac{P_{PTRS}}{P_{PUSCH}} = \frac{N_{layers} \times N_{{RE}/{layers}}}{N_{{PTRS}\mspace{14mu}{ports}} \times N_{{{RE}/{PTRS}}\mspace{14mu}{ports}}}} & (2)\end{matrix}$

Because N_(RE/layers)=N_(PTRS ports)×N_(RE/PTRS ports), a formula (3)may be further obtained:

$\begin{matrix}{\frac{P_{PTRS}}{P_{PUSCH}} = N_{layers}} & (3)\end{matrix}$

A formula (4) may be further obtained according to the formula (3):relative power ratio of the PTRS to the PUSCH=10 log₁₀(N _(layers))  (4)

Because the quantity of transport layers is equal to a quantity of DMRSports, a formula (5) may be further obtained:relative power ratio of the PTRS to the PUSCH=10 log₁₀(N_(DMRS ports))  (5)

A terminal device may obtain a relative power ratio of the PTRS to thePUSCH through calculation according to the formula (4) or (5), finallyobtain the power of the PTRS based on the power of the PUSCH, and sendthe PTRS by using the power of the PTRS.

It can be learned, through calculation according to the formula (4) or(5), that when the quantity of transport layers is 1 to 8, the quantityof DMRS ports is 1 to 8, and the quantity of PTRS ports is equal to orless than the quantity of DMRS ports, the relative power ratio of thePTRS to the PUSCH is shown in Table (1):

TABLE (1) Quantity Quantity Relative power ratio of transport of DMRS(dB) of the PTRS to layers ports the PUSCH 1 1 0 2 2 3 3 3 4.77 4 4 6 55 7 6 6 7.78 7 7 8.45 8 8 9

When the quantity of transport layers is 1 to 12, the quantity of DMRSports is 1 to 12, and the quantity of PTRS ports is equal to or lessthan the quantity of DMRS ports, Table (1) may be further extended, andthe relative power ratio of the PTRS to the PUSCH is shown in Table (2):

TABLE (2) Quantity Quantity Relative power ratio of transport of DMRS(dB) of the PTRS to layers ports the PUSCH 1 1 0 2 2 3 3 3 4.77 4 4 6 55 7 6 6 7.78 7 7 8.45 8 8 9 9 9 9.54 10 10 10 11 11 10.41 12 12 10.79

To facilitate industrial practice, rounding down may be performed on therelative power ratio of the PTRS to the PUSCH in Table (1) and Table(2). For example, when the quantity of transport layers is 3 and thequantity of DMRS ports is 3, rounding down may be performed on therelative power ratio 4.77 of the PTRS to the PUSCH to obtain a value 4.Alternatively, only a one-digit decimal may be retained for the relativepower ratio of the PTRS to the PUSCH in Table (1) and Table (2). Forexample, when the quantity of transport layers is 3 and the quantity ofDMRS ports is 3, one-digit decimal may be retained for the relativepower ratio 4.77 of the PTRS to the PUSCH to obtain a value 4.7. Whetherrounding off is performed when rounding down is performed or a one-digitdecimal is retained is not limited in this embodiment of thisapplication.

The terminal device may further search a table (for example, Table (1)or Table (2)) to obtain the relative power ratio of the PTRS to thePUSCH, finally obtain the power of the PTRS based on the power of thePUSCH, and send the PTRS by using the power of the PTRS.

In addition, in the example of uplink transmission, when transmit powerof a DMRS is equal to the transmit power of the data channel that isoriginally to be sent in the occupied RE, a formula (6) may be obtained:N _(layers) ×N′ _(RE/layers) ×P _(PUSCH) =N _(DMRS ports) ×N_(RE/DMRS ports) ×P _(DMRS)  (6)

N_(layers) is a quantity of transport layers, N_(DMRS ports) is aquantity of DMRS ports, N′_(RE/layers) is a quantity of REs at eachtransport layer (in one RB and one OFDM symbol, where the quantity ofREs is usually 12), N_(RE/DMRS ports) is a quantity of REs occupied byeach DMRS port (in one RB and one OFDM symbol), P_(DMRS) is a powerspectrum density (PSD) of the DMRS (in one RE), and P_(PUSCH) is powerof a PUSCH at the transport layer (in one RE).

A formula (7) may be further obtained according to the formula (6):

$\begin{matrix}{\frac{P_{DMRS}}{P_{PUSCH}} = \frac{N_{layers} \times N_{{RE}/{layers}}^{\prime}}{N_{{DMRS}\mspace{14mu}{ports}} \times N_{{{RE}/{DMRS}}\mspace{14mu}{ports}}}} & (7)\end{matrix}$

Because the quantity of transport layers is equal to the quantity ofDMRS ports, a formula (8) may be obtained:

$\begin{matrix}{\frac{P_{DMRS}}{P_{PUSCH}} = \frac{N_{{RE}/{layers}}^{\prime}}{N_{{{RE}/{DMRS}}\mspace{14mu}{ports}}}} & (8)\end{matrix}$

Because D_(DMRS) is a frequency domain density of the DMRS, and is equalto

$\frac{N_{{{RE}/{DMRS}}\mspace{14mu}{ports}}}{N_{{RE}/{layers}}^{\prime}},$a formula (9) may be obtained:

$\begin{matrix}{\frac{P_{DMRS}}{P_{PUSCH}} = \frac{1}{D_{DMRS}}} & (9)\end{matrix}$

A formula (10) may be further obtained according to the formula (9):

relative power ratio of the DMRS to the

$\begin{matrix}{{PUSCH} = {10\;{\log_{10}( \frac{P_{DMRS}}{P_{PUSCH}} )}}} & (10)\end{matrix}$

A formula (11) may be further obtained according to the formula (3) andthe formula (9):

$\begin{matrix}{\frac{P_{PTRS}}{P_{DMRS}} = {N_{layers}D_{DMRS}}} & (11)\end{matrix}$

A formula (12) may be further obtained according to the formula (11):

relative power ratio of the PTRS to the

$\begin{matrix}{{DMRS} = {10\;{\log_{10}( \frac{P_{PTRS}}{P_{DMRS}} )}}} & (12)\end{matrix}$

A formula (13) may be further obtained according to the formula (12):relative power ratio of the PTRS to the DMRS=10 log₁₀(N _(DMRS ports) D_(DMRS))  (13)

Because the quantity of transport layers is equal to the quantity ofDMRS ports, a formula (14) may be further obtained:relative power ratio of the PTRS to the DMRS=10 log₁₀(N _(DMRS ports) D_(DMRS))  (14)

The terminal device may obtain a relative power ratio of the PTRS to theDMRS through calculation according to the formula (13) or (14), finallyobtain the power of the PTRS based on the power of the DMRS, and sendthe PTRS by using the power of the PTRS.

It can be learned, through calculation according to the formula (13) or(14), that when the quantity of transport layers is 1 to 8, the quantityof DMRS ports is 1 to 8, and the quantity of PTRS ports is equal to orless than the quantity of DMRS ports, the relative power ratio of thePTRS to the DMRS is shown in Table (3):

TABLE (3) Quantity of Quantity of Frequency Relative power transportDMRS domain density ratio (dB) of the layers ports of the DMRS PTRS tothe DMRS 1 1 1/4 (−)6 2 2 1/4 (−)3 3 3 1/4 (−)1.23 4 4 1/4 0 5 5 1/4 0 66 1/4 0 7 7 1/4 0 8 8 1/4 3

When the quantity of transport layers is 1 to 12, the quantity of DMRSports is 1 to 12, and the quantity of PTRS ports is equal to or lessthan the quantity of DMRS ports, Table (3) may be further extended, andthe relative power ratio of the PTRS to the DMRS is shown in Table (4):

TABLE (4) Quantity of Quantity of Frequency Relative power transportDMRS domain density ratio (dB) of the layers ports of the DMRS PTRS tothe DMRS 1 1 1/4 (−)6 2 2 1/4 (−)3 3 3 1/4 (−)1.23 4 4 1/4 0 5 5 1/4 0 66 1/4 0 7 7 1/4 0 8 8 1/4 3 9 9 1/6 1.76 10 10 1/6 2.22 11 11 1/6 2.6312 12 1/6 3.01

The frequency domain density of the DMRS may be another value such as ½or ⅓. Assuming that the frequency domain density of the DMRS may be ½,⅓, ¼, or ⅙ for each quantity of transport layers or each quantity ofDMRS ports, Table (5) below may be obtained:

TABLE (5) Quantity of Quantity of Frequency Relative power ratiotransport DMRS domain density (dB) of the PTRS layers ports of the DMRSto the DMRS 1 1 1/2 −3 1 1 1/3 −4.77 1 1 1/4 −6 1 1 1/6 −7.78 2 2 1/20.00 2 2 1/3 −1.76 2 2 1/4 −3 2 2 1/6 −4.77 3 3 1/2 1.76 3 3 1/3 0.00 33 1/4 −1.25 3 3 1/6 −3 4 4 1/2 3 4 4 1/3 1.25 4 4 1/4 0.00 4 4 1/6 −1.765 5 1/2 4 5 5 1/3 2.22 5 5 1/4 0.97 5 5 1/6 −0.79 6 6 1/2 4.77 6 6 1/3 36 6 1/4 1.76 6 6 1/6 0.00 7 7 1/2 5.44 7 7 1/3 3.68 7 7 1/4 2.43 7 7 1/60.67 8 8 1/2 6 8 8 1/3 4.26 8 8 1/4 3 8 8 1/6 1.25 9 9 1/2 6.53 9 9 1/34.77 9 9 1/4 3.52 9 9 1/6 1.76 10 10 1/2 6.99 10 10 1/3 5.23 10 10 1/4 410 10 1/6 2.22 11 11 1/2 7.40 11 11 1/3 5.64 11 11 1/4 4.39 11 11 1/62.63 12 12 1/2 7.78 12 12 1/3 6 12 12 1/4 4.77 12 12 1/6 3

Table (5) provides many possibilities to configure the relative powerratio of the PTRS to the DMRS. This is not limited in this embodiment ofthis application.

In Table (3) to Table (5), because the quantity of transport layers isequal to the quantity of DMRS ports, only one of the first two columnsmay be retained. In addition, to facilitate industrial practice,rounding down may be performed on the relative power ratio of the PTRSto the DMRS in Table (3) to Table (5). For example, when the quantity oftransport layers is 9 and the quantity of DMRS ports is 9, rounding downmay be performed on the relative power ratio 1.76 of the PTRS to theDMRS to obtain a value 1. Alternatively, only a one-digit decimal may beretained for the relative power ratio of the PTRS to the DMRS in Table(3) to Table (5). For example, when the quantity of transport layers is9 and the quantity of DMRS ports is 9, a one-digit decimal may beretained for the relative power ratio 1.76 of the PTRS to the DMRS toobtain a value 1.7. Whether rounding off is performed when rounding downis performed or a one-digit decimal is retained is not limited in thisembodiment of this application.

The terminal device may search a table (for example, Table (3), Table(4), or Table (5)) to obtain the relative power ratio of the PTRS to theDMRS, finally obtain the power of the PTRS based on the power of theDMRS, and send the PTRS by using the power of the PTRS.

In a formula derivation process in this embodiment of this application,it is assumed that the quantity N_(RE/PTRS ports) of REs occupied byeach PTRS port (in one RB and one OFDM symbol) is 1. However, inimplementation, the quantity of REs occupied by each PTRS port mayalternatively be greater than 1 within one RB and one OFDM symbol,namely, N_(RE/PTRS ports)>1. In this case, a frequency domain density ofthe PTRS needs to be added to the formula (4), the formula (5), theformula (13), and the formula (14) as another variable, as shown in aformula (15):relative power ratio of the PTRS to the PUSCH=10 log₁₀(N _(layers) D_(PTRS)relative power ratio of the PTRS to the PUSCH=10 log₁₀(N _(DMRS ports) D_(PTRS))relative power ratio of the PTRS to the DMRS=10 log₁₀(N _(layers) D_(DMRS) D _(PTRS))relative power ratio of the PTRS to the DMRS=10 log₁₀(N _(DMRS ports) D_(DMRS) D _(PTRS))  (15)

D_(PTRS) is the frequency domain density of the PTRS.

Correspondingly, the relative power ratio in Table (1) to Table (5)varies with the frequency domain density of the PTRS, but may beobtained through calculation according to the formula (15).

In this embodiment of this application, after obtaining the relativepower ratio of the PTRS to the PUSCH through calculation according tothe formal (4) or (5) or by searching Table (1) or Table (2), theterminal device may finally obtain the power of the PTRS based on thepower of the PUSCH and another parameter OFFSET_(PTRS-PUSCH), and sendthe PTRS by using the power of the PTRS. OFFSET_(PTRS-PUSCH) representsa reference offset between the power of the PTRS and the power of thePUSCH, and may be configured by a base station. Similarly, afterobtaining the relative power ratio of the PTRS to the DMRS throughcalculation according to the formal (13) or (14) or by searching Table(3), Table (4), or Table (5), the terminal device may finally obtain thepower of the PTRS based on the power of the PUSCH and another parameterOFFSET_(PTRS-DMRS), and send the PTRS by using the power of the PTRS.OFFSET_(PTRS-DMRS) represents a reference offset between the power ofthe PTRS and the power of the DMRS, may be configured by the basestation, and may be obtained by accumulating OFFSET_(PTRS-PUSCH) and areference offset OFFSET_(DMRS-PUSCH) between the power of the DMRS andthe power of the PUSCH.

In this embodiment of this application, the relative power ratio of thePTRS to the PUSCH and the relative power ratio of the PTRS to the DMRSmay be preset or configured by the base station. After obtaining therelative power ratio of the PTRS to the PUSCH and the relative powerratio of the PTRS to the DMRS, the terminal device obtains the power ofthe PTRS by using the method described in this embodiment of thisapplication.

In this embodiment of this application, the base station may furtherconfigure maximum power P_(MAX) of the PTRS. When the power of the PTRSthat is obtained by the terminal device through calculation according toany formula in this embodiment of this application is greater thanP_(MAX), the terminal device sends the PTRS by using P_(MAX).

Next, in this embodiment of this application, the formula (4), theformula (5), the formula (13), and the formula (14), and Table (1) toTable (5) are verified by using an example. In the following example,DMRS ports are grouped based on different crystal oscillators, DMRSports of a same local oscillator are grouped into one group, and phasenoise of all ports in this group may be measured by using a PTRS on oneport.

FIG. 4A is a schematic diagram of a pilot pattern according to anembodiment of this application (uplink transmission, one transportlayer, one DMRS port, and one PTRS port). It can be learned from FIG. 4Athat in such a time-frequency resource mapping manner of the PTRS, thepower of the PTRS and the power of the PUSCH are consistent, and therelative power ratio of the PTRS to the PUSCH is 0 dB.

FIG. 4B-1 and FIG. 4B-2 are schematic diagrams of pilot patternsaccording to an embodiment of this application (uplink transmission, twotransport layers, two DMRS ports, and one PTRS port, where the two DMRSports are in one group). It can be learned from FIG. 4B-1 and FIG. 4B-2that FIG. 4B-1 is a schematic diagram of a pilot pattern of a transportlayer 1, and FIG. 4B-2 is a schematic diagram of a pilot pattern of atransport layer 2. Because two-layer transmission is performed, power ofa PUSCH at each layer is only half of total power, and the PTRS is sentby only one port by using the total power. Therefore, the relative powerratio of the PTRS to the PUSCH is 3 dB.

FIG. 4C-1 and FIG. 4C-2 are schematic diagrams of pilot patternsaccording to an embodiment of this application (uplink transmission, twotransport layers, two DMRS ports, and two PTRS ports, where the two DMRSports are in two groups). It can be learned from FIG. 4C-1 and FIG. 4C-2that FIG. 4C-1 is a schematic diagram of a pilot pattern of a transportlayer 1, and FIG. 4C-2 is a schematic diagram of a pilot pattern of atransport layer 2. Because of orthogonal hypothesis between the PTRS anddata, an RE for sending the PTRS at the transport layer 1 cannot bemapped to data at the transport layer 2. Therefore, power of unavailableREs may be used to increase the transmit power of the PTRS. In otherwords, to keep total power consistent, power of a PTRS sent at eachlayer should be twice power of a data channel.

It can be learned that all the formulas and tables in this embodiment ofthis application are verified in FIG. 4A to FIG. 4C-2 , and this is alsotrue for other examples of the quantity of transport layers, thequantity of DMRS ports, and the quantity of PTRS ports. No enumerationis provided herein. “Other” in FIG. 4A to FIG. 4C-2 means that whetherthe RE is mapped to a data channel, another reference signal, or othersignals is not limited. “Unavailable” means that the RE is unavailableor cannot be used for data mapping because of orthogonal multiplexing ofa PTRS and a data channel.

FIG. 5 is a schematic flowchart of a transmit power determining methodaccording to an embodiment of this application. As shown in FIG. 5 , themethod includes the following steps.

S50. A terminal device determines a relative power ratio of a PTRS to aPUSCH.

The terminal device may determine the relative power ratio of the PTRSto the PUSCH according to a formula provided in this embodiment of thisapplication or by searching a table provided in this embodiment of thisapplication, or the terminal device may further determine a relativepower ratio of the PTRS to a DMRS.

S51. The terminal device determines transmit power of the PTRS.

The terminal device determines the transmit power of PTRS based on therelative power ratio of the PTRS to the PUSCH and transmit power of thePUSCH, or determines the transmit power of the PTRS based on therelative power ratio of the PTRS to the DMRS and transmit power of theDMRS.

S52. The terminal device sends the PTRS by using the determined transmitpower.

Uplink transmission is used as an example for description in thisembodiment of this application. For downlink transmission, because a newradio (NR) system uses an uplink-downlink symmetrical pilot pattern ofthe DMRS and an uplink-downlink symmetrical pilot pattern of the PTRS,all formulas and tables in this embodiment of this application are alsoapplicable to downlink PTRS power determining, providing that therelated “PUSCH” changes to a “PDSCH”.

In this embodiment of this application, after a base station deviceobtains a pilot pattern, when a pilot pattern of a to-be-sent PTRSconflicts with a pilot pattern of another to-be-sent reference signal(i.e., a reference signal other than the PTRS), in other words, when thepilot pattern indicates that the to-be-sent PTRS and the anotherto-be-sent reference signal need to occupy a same RE or several same REs(a conflicting RE), the PTRS is not allowed to occupy an RE of theanother reference signal (i.e., a priority of sending the anotherreference signal is higher than a priority of sending the PTRS). In thiscase, the base station device maps the another to-be-sent referencesignal to the conflicting RE, and sends only the another referencesignal on the conflicting RE. The transmit power of the PTRS may bedetermined by using the method described in the foregoing embodiment.

Alternatively, the to-be-sent PTRS is allowed to occupy an RE of theanother to-be-sent reference signal. In this case, the base stationdevice maps the to-be-sent PTRS to the conflicting RE, and sends onlythe PTRS on the conflicting RE. In addition, power of an RE originallyused to send the another reference signal (excluding the conflicting REmapped to the to-be-sent PTRS) may be used to increase the power of thePTRS.

In this embodiment of this application, the following expressions have asame meaning: an RE that cannot be used for data mapping, an RE that isnot used for data mapping, an RE that is not mapped to data, and a mutedRE. Generally, in this embodiment of this application, power of an REthat is not mapped to data is used to increase the power of the PTRS. Arelative power ratio of the PTRS after the increment to data (which mayalso be referred to as “a difference between the power of the PTRS andpower of the data) is equal to a logarithm of a quantity of transportlayers (the quantity of transport layers is greater than or equal to 2during multi-layer transmission), namely 10 log₁₀ (N_(layers)). When aquantity of PTRS ports is equal to a quantity of DMRS ports, to ensureorthogonal multiplexing of PTRSs and data at different transport layersof the terminal device, some REs at a specific transport layer are notmapped to data, and power of these REs that are not mapped to the datais used to increase power of a PTRS at the transport layer. In thiscase, a relative power ratio of a PTRS to data at each transport layeris equal to the logarithm of the quantity of transport layers. When thequantity of PTRS ports is less than the quantity of DMRS ports, powermay be “borrowed” across layers. In other words, power of an RE at aspecific transport layer that is not mapped to data is used to increasepower of a PTRS at another transport layer, and a relative power ratioof transmit power of the PTRS to data at the transport layer of the PTRSis equal to the logarithm of the quantity of transport layers.

In this embodiment of this application, a transmit end device firstobtains the relative power ratio of the PTRS to the data channel or tothe DMRS by searching a table or through calculation, determines thetransmit power of the PTRS based on the transmit power of the datachannel or the transmit power of the DMRS, and sends the PTRS by usingthe transmit power, so that different quantities of DMRS ports,different quantities of PTRS ports, and different port multiplexingmanner configurations can be flexibly adapted, thereby ensuringefficient energy use.

FIG. 6 is a schematic structural diagram of hardware of a communicationsdevice 60 according to an embodiment of this application. As shown inFIG. 6 , the communications device 60 includes a memory 61, a processor62, and a transmitter 63.

The memory 61 is configured to store program code including a computeroperation instruction.

The processor 62 is configured to execute the computer operationinstruction to perform the following operations:

determining a relative power ratio of a phase tracking reference signal(PTRS) to a data channel or a relative power ratio of a PTRS to ademodulation reference signal (DMRS). The relative power ratio of thePTRS to the data channel is determined by using a first function and afirst variable, the relative power ratio of the PTRS to the DMRS isdetermined by using a second function, the first variable, and a secondvariable. The first variable includes a quantity of transport layers ora quantity of DMRS ports, and the second variable includes a frequencydomain density of the DMRS; and

determining transmit power of the PTRS based on the relative power ratioof the PTRS to the data channel and transmit power of the data channelor based on the relative power ratio of the PTRS to the DMRS andtransmit power of the DMRS.

The transmitter 63 is configured to send the PTRS to anothercommunications device by using the transmit power of the PTRS.

Optionally, the processor 62 is configured to execute the computeroperation instruction to perform the following operations:

searching a table to determine a relative power ratio of a PTRS to adata channel or a relative power ratio of a PTRS to a d DMRS; and

determining transmit power of the PTRS based on the relative power ratioof the PTRS to the data channel and transmit power of the data channelor based on the relative power ratio of the PTRS to the DMRS andtransmit power of the DMRS.

Embodiment 2

Different from Embodiment 1 in which the transmit end first obtains therelative power ratio of the PTRS to the data channel or to the DMRS, andthen determines the transmit power of the PTRS based on the transmitpower of the data channel or the transmit power of the DMRS, in thisembodiment of this application, the transmit power of the PTRS isdirectly obtained through calculation.

In an LTE system, uplink transmit power needs to meet a requirement of asignal to interference plus noise ratio (SINR) required when a bit errorrate of data transmission on a PUSCH reaches 10% based on differentmodulation and coding schemes (MCS). A base station device determinestransmit power of the PUSCH based on this requirement.

In an example of uplink transmission, a formula for calculating transmitpower of a data channel may be:

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min\begin{Bmatrix}{{10\;{\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} )}},} \\\begin{matrix}{{10\;{\log_{10}( {M_{{PUSCH},c}(i)} )}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}} & (16)\end{matrix}$

In the formula (16), i represents a subframe number (or a timeslotnumber or a symbol number), c represents a cell number (or a beam numberor a beam group number), and j represents a preset value, and may bepreset or configured by the base station device;

P_(PUSCH,c)(i) represents transmit power used by a terminal device tosend the PUSCH to a cell c in a subframe i;

{circumflex over (P)}_(CMAX,c)(i) is a linear value of P_(CMAX,c(i)),and P_(CMAX,c)(i) represents available transmit power of the terminaldevice;

{circumflex over (P)}_(PUCCH)(i) is a linear value of P_(PUCCH)(i), andP_(PUCCH)(i) represents transmit power used by the terminal device tosend the PUCCH in the subframe i;

M_(PUSCH,c)(i) represents bandwidth occupied by a PUSCH resource in thesubframe i, and is expressed in a quantity of RBs;

P_(O_PUSCH,c)(i) represents reference power of the PUSCH, andP_(O_PUSCH,c)(j)=P_(O_UE_PUSCH,c)(j)+P_(O_NOMINAL_PUSCH,c)(j), whereP_(O_NOMINAL_PUSCH,c)(j) represents a semi-static transmit powerreference in the cell c, and is usually a common value configured by thebase station device for all terminal devices in the cell, andP_(O_UE_PUSCH,c)(j) represents a power offset of a semi-static transmitpower reference of each terminal device in the cell c, and is usually aspecific value configured by the base station device for each terminaldevice;

α_(c)(j) represents a path loss compensation degree;

PL_(c) represents a path loss value obtained after the terminal devicemeasures a reference signal (for example, a channel stateinformation-reference signal (CSI-RS), a cell-specific reference signal(CRS), or a synchronization signal block (SS Block for short)) of thecell c;

Δ_(TF,c)(i) represents that transmit power of each RB is allowed to beadaptive to an information data transmission rate according to atransmission format; and

f_(c)(i) represents closed-loop power control specific to the terminaldevice that may be classified into an accumulated value and an absolutevalue. A mode that is to be used is determined by using anaccumulationEnable (whether TPC accumulation is used) parameterconfigured by the base station device. If the TPC accumulation is used,f_(c)(i)=f_(c)(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)) that is, f_(c)(i) is a sumof an accumulated TPC value before an i^(th) subframe and a TPC valueδ_(PUSCH,c) indicated by downlink control information (DCI) received inan (i-K_(PUSCH))^(th) subframe.

In this embodiment of this application, considering that the PTRS isused for phase tracking to assist data demodulation, when the transmitpower of the PTRS is directly obtained through calculation, a transmitpower determining method may be obtained based on some parameters in theformula (16). The method includes the following steps:

A terminal device obtains a preset adjustment parameter and transmissionbandwidth of a PTRS.

The terminal device determines transmit power of the PTRS, where thetransmit power of the PTRS is determined by using at least a presetfunction, an adjustment parameter, and the transmission bandwidth of thePTRS.

The terminal device sends the PTRS to a base station device by using thetransmit power of the PTRS.

In this embodiment of this application, considering that the PTRS isused for phase tracking to assist data demodulation, when the transmitpower of the PTRS is directly obtained through calculation, the transmitpower of the PTRS may be determined based on some parameters in theformula (16) according to the following formula:

$\begin{matrix}{{P_{{PTRS},c}(i)} = {\min\begin{Bmatrix}{P_{{CMAX},c}(i)} \\\begin{matrix}{{P_{{PTRS\_ OFFSET},c}(m)} + {10\;{\log_{10}( M_{{PTRS},c} )}} +} \\{{P_{{O\_ PUSCH},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}} & (17)\end{matrix}$

In the formula (17), parameters P_(CMAX,c)(i), P_(O_PUSCH,c)(j),α_(c)(j), PL_(c), and f_(c)(i) are all reused from the formula (16). Inaddition, P_(PTRS,c)(i) represents the transmit power of the PTRS thatincludes transmit power used by the terminal device to send the PTRS tothe cell c in the subframe i and whose value is in a unit of dBm,M_(PTRS,c) represents the transmission bandwidth of the PTRS,P_(PTRS_OFFSET,c)(m) represents the present adjustment parameter, and mis equal to 0 or 1.

In this embodiment of this application, the base station device mayconfigure or preset a parameter by using RRC signaling or DCI.

In this embodiment of this application, the transmit power of the PTRSis directly obtained through calculation, so that the terminal devicecan conveniently determine the transmit power of the PTRS.

Embodiment 3

This embodiment of this application provides another method for directlyobtaining transmit power of a PTRS through calculation. The methodincludes the following steps:

A terminal device obtains reference power of a PTRS.

The terminal device determines transmit power of the PTRS, where thetransmit power of the PTRS is determined by using at least a presetfunction and the reference power of the PTRS.

The terminal device sends the PTRS to a base station device by using thetransmit power of the PTRS.

The terminal device may determine the transmit power of the PTRSaccording to the following formula:

$\begin{matrix}{{P_{{PTRS},c}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{P_{{O\_ PTRS},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}}}\end{Bmatrix}}} & (18)\end{matrix}$

In the formula (18), meanings of parameters P_(PTRS,c)(i),P_(CMAX,c)(i), α_(c)(j), and PL_(c) are the same as those of theparameters in the formula (17). In addition, P_(O_PTRS,c)(j) representsthe reference power of the PTRS, andP_(O_PTRS,c)(j)=P_(O_NOMINAL_PTRS)+P_(O_UE_PTRS), whereP_(O_NOMINAL_PTRS) represents a common value configured by the basestation device for all terminal devices in a cell c, and P_(O_UE_PTRS)represents a specific value configured by the base station device foreach terminal device in the cell c.

Further, a parameter g(i) may be further added to the formula (18), sothat each terminal device can adjust the transmit power of the PTRSbased on a condition of the terminal device, as shown in the followingformula:

$\begin{matrix}{{{P_{{PTRS},c}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{P_{{O\_ PTRS},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {g(i)}}\end{Bmatrix}}},} & (19)\end{matrix}$where

g(i) represents an adjustment parameter specific to the terminal device.

Further, parameters h(n_(RS)), Δ_(PTRS)(F), and Δ_(T×D)(N_(PTRS-port))may be further added to the formula (18) to obtain the followingformula:

$\begin{matrix}{{P_{{PTRS},c}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{{P_{{O\_ PTRS},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {h( n_{RS} )} +} \\{{\Delta_{PTRS}(F)} + {\Delta_{TxD}( N_{{PTRS} - {port}} )} + {g(i)}}\end{matrix}\end{Bmatrix}}} & (20)\end{matrix}$

In the formula (20), n_(RS) represents a priority parameter of the PTRS,and h(n_(RS)) represents a power offset obtained by the terminal deviceby using n_(RS);

F represents a pilot pattern, Δ_(PTRS)(F) represents an adjustment valuecorresponding to the pilot pattern, and different pilot patterns arecorresponding to different adjustment values; and

N_(PTRS-port) represents a quantity of antenna ports for sending thePTRS, Δ_(T×D)(N_(PTRS-port)) represents a power adjustment valuecorresponding to the quantity of antenna ports, and different quantitiesof antenna ports are corresponding to different adjustment values.

In this embodiment of this application, the transmit power of the PTRSis directly obtained through calculation, so that the terminal devicecan conveniently determine the transmit power of the PTRS.

The transmit power determining method provided in Embodiment 2 andEmbodiment 3 may be performed by the communications device shown in FIG.6 . For example, the memory 61 is configured to store program codeincluding a computer operation instruction. The processor 62 isconfigured to: obtain a required parameter, and obtain transmit power ofa PTRS by using the parameter and the formulas (17) to (20). Thetransmitter 63 is configured to send the PTRS to another communicationsdevice by using the transmit power of the PTRS.

An embodiment of this application further provides a computer readablestorage medium, configured to store a computer software instruction thatneeds to be executed by the foregoing processor. The computer softwareinstruction includes a program that needs to be executed by theforegoing processor.

A person skilled in the art should understand that the embodiments ofthis application may be provided as a method, a system, or a computerprogram product. Therefore, this application may use a form of hardwareonly embodiments, software only embodiments, or embodiments with acombination of software and hardware. Moreover, the present disclosuremay use a form of a computer program product that is implemented on oneor more computer-usable storage media (including but not limited to adisk memory, an optical memory, and the like) that includecomputer-usable program code.

This application is described with reference to the flowcharts and/orblock diagrams of the method, the device (system), and the computerprogram product according to this application. It should be understoodthat computer program instructions may be used to implement each processand/or each block in the flowcharts and/or the block diagrams and acombination of a process and/or a block in the flowcharts and/or theblock diagrams. These computer program instructions may be provided fora general-purpose computer, a dedicated computer, an embedded processor,or a processor of any other programmable data processing device togenerate a machine, so that the instructions executed by a computer or aprocessor of any other programmable data processing device generate anapparatus for implementing a specific function in one or more processesin the flowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readablememory that can instruct the computer or any other programmable dataprocessing device to work in a specific manner, so that the instructionsstored in the computer readable memory generate an artifact thatincludes an instruction apparatus. The instruction apparatus implementsa specific function in one or more processes in the flowcharts and/or inone or more blocks in the block diagrams.

These computer program instructions may be loaded onto a computer oranother programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

Obviously, a person skilled in the art can make various modificationsand variations to this application without departing from the scope ofthis application. This application is intended to cover thesemodifications and variations of this application provided that they fallwithin the scope of protection defined by the following claims and theirequivalent technologies.

What is claimed is:
 1. A method comprising: determining a power ratiobetween a phase tracking reference signal (PTRS) and a data channelaccording to a mapping relationship between a quantity of transportlayers and the power ratio, wherein the power ratio is used fordetermining a transmit power of the PTRS; and wherein the mappingrelationship comprises: the power ratio between the PTRS and the datachannel is 3 dB when the quantity of transport layers is 2; the powerratio between the PTRS and the data channel is 4.77 dB when the quantityof transport layers is 3; and the power ratio between the PTRS and thedata channel is 6 dB when the quantity of transport layers is 4, whereina quantity of one or more PTRS ports for the PTRS is less than thequantity of transport layers.
 2. The method according to claim 1,wherein the data channel is a physical uplink shared channel (PUSCH). 3.The method according to claim 1, wherein the mapping relationshipfurther comprises: the power ratio between the PTRS and the data channelis 7 dB when the quantity of transport layers is 5; and the power ratiobetween the PTRS and the data channel is 7.78 dB when the quantity oftransport layers is
 6. 4. The method according to claim 3, wherein thedata channel is a physical downlink shared channel (PDSCH).
 5. Themethod according to claim 1, wherein the power ratio is a power ratio ofa resource element (RE) level, the RE is a minimum unit in atime-frequency domain.
 6. A method comprising: receiving a phasetracking reference signal (PTRS); receiving a data channel mapped to aplurality of transport layers; and wherein a power ratio between thePTRS and the data channel and a quantity of the plurality of transportlayers meet a mapping relationship comprising: the power ratio betweenthe PTRS and the data channel is 3 dB when the quantity of transportlayers is 2; the power ratio between the PTRS and the data channel is4.77 dB when the quantity of transport layers is 3; and the power ratiobetween the PTRS and the data channel is 6 dB when the quantity oftransport layers is 4, wherein a quantity of one or more PTRS ports forthe PTRS is less than the quantity of transport layers.
 7. The methodaccording to claim 6, wherein the data channel is a physical uplinkshared channel (PUSCH).
 8. The method according to claim 6, wherein themapping relationship further comprises: the power ratio between the PTRSand the data channel is 7 dB when the quantity of transport layers is 5;and the power ratio between the PTRS and the data channel is 7.78 dBwhen the quantity of transport layers is
 6. 9. The method according toclaim 8, wherein the data channel is a physical downlink shared channel(PDSCH).
 10. The method according to claim 6, wherein the power ratio isa power ratio of a resource element (RE) level, the RE is a minimum unitin a time-frequency domain.
 11. An apparatus comprising: a processorconfigured to perform computer operation instructions of a memory,causing the apparatus to provide at least the following operations:determining a power ratio between a phase tracking reference signal(PTRS) and a data channel according to a mapping relationship between aquantity of transport layers and the power ratio, wherein the powerratio is used for determining a transmit power of the PTRS; and whereinthe mapping relationship comprises: the power ratio between the PTRS andthe data channel is 3 dB when the quantity of transport layers is 2; thepower ratio between the PTRS and the data channel is 4.77 dB when thequantity of transport layers is 3; and the power ratio between the PTRSand the data channel is 6 dB when the quantity of transport layers is 4,wherein a quantity of one or more PTRS ports for the PTRS is less thanthe quantity of transport layers.
 12. The apparatus according to claim11, wherein the data channel is a physical uplink shared channel(PUSCH).
 13. The apparatus according to claim 11, wherein the mappingrelationship further comprises: the power ratio between the PTRS and thedata channel is 7 dB when the quantity of transport layers is 5; and thepower ratio between the PTRS and the data channel is 7.78 dB when thequantity of transport layers is
 6. 14. The apparatus according to claim13, wherein the data channel is a physical downlink shared channel(PDSCH).
 15. The apparatus according to claim 11, wherein the powerratio is a power ratio of a resource element (RE) level, the RE is aminimum unit in a time-frequency domain.
 16. An apparatus comprising: aprocessor configured to perform computer operation instructions of amemory, causing the apparatus to perform at least the followingoperations: receiving a phase tracking reference signal (PTRS);receiving a data channel mapped to a plurality of transport layers; andwherein a power ratio between the PTRS and the data channel and aquantity of the plurality of transport layers meet a mappingrelationship comprising: the power ratio between the PTRS and the datachannel is 3 dB when the quantity of transport layers is 2; the powerratio between the PTRS and the data channel is 4.77 dB when the quantityof transport layers is 3; and the power ratio between the PTRS and thedata channel is 6 dB when the quantity of transport layers is 4, whereina quantity of one or more PTRS ports for the PTRS is less than thequantity of transport layers.
 17. The apparatus according to claim 16,wherein the data channel is a physical uplink shared channel (PUSCH).18. The apparatus according to claim 16, wherein the mappingrelationship further comprises: the power ratio between the PTRS and thedata channel is 7 dB when the quantity of transport layers is 5; and thepower ratio between the PTRS and the data channel is 7.78 dB when thequantity of transport layers is
 6. 19. The apparatus according to claim18, wherein the data channel is a physical downlink shared channel(PDSCH).
 20. The apparatus according to claim 16, wherein the powerratio is a power ratio of a resource element (RE) level, the RE is aminimum unit in a time-frequency domain.